It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplas...It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplasmic proteins.However,increasing evidence suggests that nuclear mechanotransduction impacts nuclear activities and functions.Recently we have revealed that transgene dihydrofolate reductase(DHFR)gene expression is directly upregulated via cell surface forceinduced stretching of chromatin [2].Here we show that endogenous genes are also upregulated directly by force via integrins.We present evidence on an underlying mechanism of how gene transcription is regulated by force.We have developed a technique of elastic round microgels to quantify 3D tractions in vitro and in vivo[3].We report a synthetic small molecule(which has been stiffened structurally)that inhibits malignant tumor repopulating cell growth in a low-stiffness(force)microenvironment and cancer metastasis in mouse models without detectable toxicity[4].These findings suggest that direct nuclear mechanotransduction impacts mechanobiology and mechanomedicine at cellular and molecular levels.展开更多
Evolution of eukaryotes from simple cells to complex multicellular organisms remains a mystery. Our postulate is that cytoskeletal stiffening is a necessary condition for evolution of complex multicellular organisms f...Evolution of eukaryotes from simple cells to complex multicellular organisms remains a mystery. Our postulate is that cytoskeletal stiffening is a necessary condition for evolution of complex multicellular organisms from early simple eukaryotes. Recent findings show that embryonic stem cells are as soft as primitive eukaryotes-amoebae and that differentiated tissue cells can be two orders of magnitude stiffer than embryonic stem cells. Soft embryonic stem cells become stiff as they differentiate into tissue cells of the complex multicellular organisms to match their microenvironment stiffness. We perhaps see in differentiation of embryonic stem cells (derived from inner cell mass cells) the echo of those early evolutionary events. Early soft unicellular organisms might have evolved to stiffen their cytoskeleton to protect their structural integrity from external mechanical stresses while being able to maintain form, to change shape, and to move.展开更多
It is well established that living cells and tissues respond to mechanical forces such as flow-related shear stresses in blood or interstitial space and complex tractional stresses at cell-matrix contacts and cell-cel...It is well established that living cells and tissues respond to mechanical forces such as flow-related shear stresses in blood or interstitial space and complex tractional stresses at cell-matrix contacts and cell-cell contacts.However,how different modes of forces impact mechanical and biological responses is elusive.Here we describe a strategy of using the three-dimensional magnetic twisting cytometry(3D MTC)technology to apply forces in any desired directions to the same living cell.We reveal that for a fixed stress amplitude and frequency,a live cell exhibits mechanical anisotropy and responds to a local shear stress differently from responding to a local complex stress by stretching chromatin and upregulating gene transcription to different levels,extending our previous finding on force-induced direct gene activation.This finding highlights the importance of force modes in impacting cellular mechanical and biological responses in living cells and tissues and may have implications in tissue patterning and embryonic development.展开更多
All living cells in a human body are made of the same DNA molecule but cells in different tissues express different genes and proteins.How the transcription process is controlled and regulated is largely unknown.Speci...All living cells in a human body are made of the same DNA molecule but cells in different tissues express different genes and proteins.How the transcription process is controlled and regulated is largely unknown.Specifically,mechanical forces are increasingly recognized to play critical roles in cell and tissue functions.However,what controls force-induced gene transcription is elusive.Recently we have reported that a local surface force transfers from integrins to the cytoskeleton and the link of nucleoskeleton and the cytoskeleton(LINC)into the nucleus and deforms chromatin directly to induce rapid activation of transgene DHFR.Here we show that endogenous mechanoresponsive genes egr-1 and Cav1 are rapidly upregulated and their upregulation depends on stress angles relative to the cell long axis,suggesting direct impact of these genes by force.Demethylation of histone 3 at lysine 9(H3K9)trimethylation(H3K9me3)at nuclear interiors(euchromatin)is necessary for force-induced transcription upregulation.Our findings suggest that force-rapid upregulation of mechanoresponsive genes by force depends on H3K9me3 demethylation.展开更多
Spinal cord injury repair is one of the major challenges in medicine,as it can lead to permanent loss of function of central nervous system and damage to other function of the body.Stem cell transplantation together w...Spinal cord injury repair is one of the major challenges in medicine,as it can lead to permanent loss of function of central nervous system and damage to other function of the body.Stem cell transplantation together with tissue engineering is increasingly becoming a potential choice of treatment.However,direct transplantation of stem cells without scaffolds has yielded poor clinical outcome.Here we show a strategy of using mouse embryonic stem cells(ESCs)cultured within a silk fibroin(SF)based,three-dimensional scaffold with oriented channels by a directional temperature field freezing technique and lysophilization.We find that the ESCs maintained proliferation and migrated in the scaffolds and the cells migrated fastest along the SF channels.SF scaffolds contributed to ESC differentiation into neural and glial cell like cells and expressions of the neural and glial cell markers MAP2 and GFAP were greatly elevated when retinoic acid was used as an inducing factor.Our results suggest that this approach may offer some hope in the future for spinal cord injury repair using SF scaffolds and ESCs.展开更多
Immune cells play key roles in cancer and chronic inflammatory disease. A better understanding of the mechanisms and risks will help develop novel target therapies. At the 2017 International Workshop of the Chinese Ac...Immune cells play key roles in cancer and chronic inflammatory disease. A better understanding of the mechanisms and risks will help develop novel target therapies. At the 2017 International Workshop of the Chinese Academy of Medical Sciences Initiative for Innovative Medicine on Tumor Immunology held in Beijing, China, on May 12, 2017, a number of speakers reported new findings and ongoing studies on immune-related diseases such as cancer, fibrotic disease, diabetes, and others. A considerably insightful overview was provided on cancer immunity, tumor microenvironments,and new immunotherapy for cancer. In addition, chronic inflammatory diseases were discussed. These findings may offer new insights into targeted immunotherapy.展开更多
The technology of induced pluripotent stem cell(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement thera...The technology of induced pluripotent stem cell(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement therapies and drug screening,but the potential risk of tumorigenesis hampers further development and application.How to generate required differentia-ted cells without initiating tumor progression remains a huge challenge.Here we show that mouse embryonic fibroblasts could be differentiated into valvular endothelial cell(VEC)like cells.VECs are critical in valve replacements in aortic valve failure.VEC-associated gene and protein expression and functional assays were quantified for these VEC-like cells.We show that mouse embryonic fibroblasts could be converted into VEC-like cells.Our results suggest that it is possible to convert mouse embryonic fibroblasts into VEC-like cells without first reprogramming them into pluripotent stem cells,minimizing the possibility of tumorigenesis.展开更多
Recently we have synthesized a novel small retinoid molecule WYC-209 that can effectively inhibit proliferation of malignant murine melanoma tumor-repopulating cells(TRCs).The molecule can induce 100%TRCs apoptosis at...Recently we have synthesized a novel small retinoid molecule WYC-209 that can effectively inhibit proliferation of malignant murine melanoma tumor-repopulating cells(TRCs).The molecule can induce 100%TRCs apoptosis at 10μM concentration.However,how WYC-209 induces TRCs apoptosis is still elusive.Here we demonstrate that WYC-209 at>6μM concentration started to induce TRCs apoptosis primarily via the caspase 3 pathway by releasing cytochrome c from mitochondria.Interestingly,we found that at concentrations<6μM WYC-209 induced TRCs to elevate dormancy marker COUP TF1 but induced no changes in apoptosis marker P53.Furthermore,proliferation markers Ki67 and PCNA decreased with the increase of WYC-209 concentrations,suggesting that low concentrations of WYC-209 inhibit TRCs growth by inducing cell dormancy instead of causing apoptosis.In addition,TRC traction forces were almost abolished when WYC-209 concentration was at 5μM,preceding the initiation of apoptosis.Our findings demonstrate that inhibition of TRCs by anti-cancer molecule WYC-209 is concentration-dependent and WYC-209 inhibits cellular force generation of the tumor-repopulating cells before inducing apoptosis.展开更多
Different types of pores ubiquitously form in cell membranes,leading to various types of cell death that profoundly influence the fate of inflammation and the disease status.However,these pores have never truly been v...Different types of pores ubiquitously form in cell membranes,leading to various types of cell death that profoundly influence the fate of inflammation and the disease status.However,these pores have never truly been visualized to date.Atomic force microscopy(AFM),which is emerging as a powerful tool to analyze the mechanical properties of biomolecules and cells,is actually an excellent imaging platform that allows biological samples to be visualized by probing surface roughness at the level of atomic resolution.Here,membrane pore structures were clearly visualized using AFM.This visualization not only describes the aperture and depth of the pore complexes but also highlights differences among the pores formed by perforin and gasdermins in tumor cell membranes and by complement in immune cell membranes.Additionally,this type of visualization also reveals the dynamic process of pore formation,fusion,and repair.展开更多
基金supported by funds from National Institutes of Health,USA and Huazhong University of Science and Technology,Wuhan,Chinathe support from Hoeft Professorship at University of Illinois at Urbana-Champaign
文摘It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplasmic proteins.However,increasing evidence suggests that nuclear mechanotransduction impacts nuclear activities and functions.Recently we have revealed that transgene dihydrofolate reductase(DHFR)gene expression is directly upregulated via cell surface forceinduced stretching of chromatin [2].Here we show that endogenous genes are also upregulated directly by force via integrins.We present evidence on an underlying mechanism of how gene transcription is regulated by force.We have developed a technique of elastic round microgels to quantify 3D tractions in vitro and in vivo[3].We report a synthetic small molecule(which has been stiffened structurally)that inhibits malignant tumor repopulating cell growth in a low-stiffness(force)microenvironment and cancer metastasis in mouse models without detectable toxicity[4].These findings suggest that direct nuclear mechanotransduction impacts mechanobiology and mechanomedicine at cellular and molecular levels.
文摘Evolution of eukaryotes from simple cells to complex multicellular organisms remains a mystery. Our postulate is that cytoskeletal stiffening is a necessary condition for evolution of complex multicellular organisms from early simple eukaryotes. Recent findings show that embryonic stem cells are as soft as primitive eukaryotes-amoebae and that differentiated tissue cells can be two orders of magnitude stiffer than embryonic stem cells. Soft embryonic stem cells become stiff as they differentiate into tissue cells of the complex multicellular organisms to match their microenvironment stiffness. We perhaps see in differentiation of embryonic stem cells (derived from inner cell mass cells) the echo of those early evolutionary events. Early soft unicellular organisms might have evolved to stiffen their cytoskeleton to protect their structural integrity from external mechanical stresses while being able to maintain form, to change shape, and to move.
基金supported by funds Huazhong University of Science and Technology,Wuhan,China and from US National Institutes of Health
文摘It is well established that living cells and tissues respond to mechanical forces such as flow-related shear stresses in blood or interstitial space and complex tractional stresses at cell-matrix contacts and cell-cell contacts.However,how different modes of forces impact mechanical and biological responses is elusive.Here we describe a strategy of using the three-dimensional magnetic twisting cytometry(3D MTC)technology to apply forces in any desired directions to the same living cell.We reveal that for a fixed stress amplitude and frequency,a live cell exhibits mechanical anisotropy and responds to a local shear stress differently from responding to a local complex stress by stretching chromatin and upregulating gene transcription to different levels,extending our previous finding on force-induced direct gene activation.This finding highlights the importance of force modes in impacting cellular mechanical and biological responses in living cells and tissues and may have implications in tissue patterning and embryonic development.
基金supported by the funds from Huazhong University of Science and Technology and US NIH grant GM 072744
文摘All living cells in a human body are made of the same DNA molecule but cells in different tissues express different genes and proteins.How the transcription process is controlled and regulated is largely unknown.Specifically,mechanical forces are increasingly recognized to play critical roles in cell and tissue functions.However,what controls force-induced gene transcription is elusive.Recently we have reported that a local surface force transfers from integrins to the cytoskeleton and the link of nucleoskeleton and the cytoskeleton(LINC)into the nucleus and deforms chromatin directly to induce rapid activation of transgene DHFR.Here we show that endogenous mechanoresponsive genes egr-1 and Cav1 are rapidly upregulated and their upregulation depends on stress angles relative to the cell long axis,suggesting direct impact of these genes by force.Demethylation of histone 3 at lysine 9(H3K9)trimethylation(H3K9me3)at nuclear interiors(euchromatin)is necessary for force-induced transcription upregulation.Our findings suggest that force-rapid upregulation of mechanoresponsive genes by force depends on H3K9me3 demethylation.
基金supported by funds from Huazhong University of Science and Technology,Wuhan,China
文摘Spinal cord injury repair is one of the major challenges in medicine,as it can lead to permanent loss of function of central nervous system and damage to other function of the body.Stem cell transplantation together with tissue engineering is increasingly becoming a potential choice of treatment.However,direct transplantation of stem cells without scaffolds has yielded poor clinical outcome.Here we show a strategy of using mouse embryonic stem cells(ESCs)cultured within a silk fibroin(SF)based,three-dimensional scaffold with oriented channels by a directional temperature field freezing technique and lysophilization.We find that the ESCs maintained proliferation and migrated in the scaffolds and the cells migrated fastest along the SF channels.SF scaffolds contributed to ESC differentiation into neural and glial cell like cells and expressions of the neural and glial cell markers MAP2 and GFAP were greatly elevated when retinoic acid was used as an inducing factor.Our results suggest that this approach may offer some hope in the future for spinal cord injury repair using SF scaffolds and ESCs.
基金supported by grants of 81530093 from the National Natural Science Foundation of China81661128007, 81472653 and 81530080 from National Natural Science Foundation of China+26 种基金supported by grants of 31390431 from the National Natural Science Foundation of Chinasupported by grants of Natural Sciences Foundation of China(31301007 and 81272525)supported by grants of 81622010 from the National Natural Science Foundation of Chinasupported by grants of 81472717 and 81673474 from the National Natural Science Foundation of China81661128007, 81472653 and 81530080 from National Natural Science Foundation of Chinasupported by grants of 81400286 and 81530093 from the National Natural Science Foundation of Chinasupported by grants of 81400140 from the National Natural Science Foundation of Chinasupported by grants of 81503128 from the National Natural Science Foundation of China2016I2M-1-008 from Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciencessupported by grants of 2014CB542103 from National Basic Research Program of China81502473 from National Natural Science Fund for Young Scholars of Chinasupported by US National Institutes of Health grants (CA217510, CA123088, CA099985, CA193136 and CA152470)supported by grants from the Canadian Institutes of Health Research(FRN 123516 and 152954)the Ontario Institute for Cancer Research(ORBiT)supported by NIH grant GM072744Ministry of Science and Technology of China grant 2016YFA0101100the Fundamental Research Fund for the Central University(No. 2017KFQWJX002) from Huazhong University of Science and TechnologyCore fund (Wang2016) for Development of Cell and Gene Therapy Centre of Academy of Medical Sciences,Zhengzhou UniversityThe MRC (MR/M015696/1)2017YFA0205400 from Ministry of Science and Technology of China2016ZX310190 and 2016ZX320014 from Central Public-interest Scientific Institution Basal Research Fund7162133 from Beijing Natural Science Foundation2016-I2M-4-001 from CAMS Innovation Fund for Medical Sciences2016-I2M-1-007 from the CAMS Innovation Fund for Medical Sciences2016-I2M-1010 from the CAMS Innovation Fund for Medical Sciences2016-I2M-1011 from the CAMS Innovation Fund for Medical Sciences2016-I2M-1008 from CAMS Innovation Fund for Medical Sciences
文摘Immune cells play key roles in cancer and chronic inflammatory disease. A better understanding of the mechanisms and risks will help develop novel target therapies. At the 2017 International Workshop of the Chinese Academy of Medical Sciences Initiative for Innovative Medicine on Tumor Immunology held in Beijing, China, on May 12, 2017, a number of speakers reported new findings and ongoing studies on immune-related diseases such as cancer, fibrotic disease, diabetes, and others. A considerably insightful overview was provided on cancer immunity, tumor microenvironments,and new immunotherapy for cancer. In addition, chronic inflammatory diseases were discussed. These findings may offer new insights into targeted immunotherapy.
基金supported by funds from Huazhong University of Science and Technology
文摘The technology of induced pluripotent stem cell(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement therapies and drug screening,but the potential risk of tumorigenesis hampers further development and application.How to generate required differentia-ted cells without initiating tumor progression remains a huge challenge.Here we show that mouse embryonic fibroblasts could be differentiated into valvular endothelial cell(VEC)like cells.VECs are critical in valve replacements in aortic valve failure.VEC-associated gene and protein expression and functional assays were quantified for these VEC-like cells.We show that mouse embryonic fibroblasts could be converted into VEC-like cells.Our results suggest that it is possible to convert mouse embryonic fibroblasts into VEC-like cells without first reprogramming them into pluripotent stem cells,minimizing the possibility of tumorigenesis.
基金supported by funds from Huazhong University of Science and Technology
文摘Recently we have synthesized a novel small retinoid molecule WYC-209 that can effectively inhibit proliferation of malignant murine melanoma tumor-repopulating cells(TRCs).The molecule can induce 100%TRCs apoptosis at 10μM concentration.However,how WYC-209 induces TRCs apoptosis is still elusive.Here we demonstrate that WYC-209 at>6μM concentration started to induce TRCs apoptosis primarily via the caspase 3 pathway by releasing cytochrome c from mitochondria.Interestingly,we found that at concentrations<6μM WYC-209 induced TRCs to elevate dormancy marker COUP TF1 but induced no changes in apoptosis marker P53.Furthermore,proliferation markers Ki67 and PCNA decreased with the increase of WYC-209 concentrations,suggesting that low concentrations of WYC-209 inhibit TRCs growth by inducing cell dormancy instead of causing apoptosis.In addition,TRC traction forces were almost abolished when WYC-209 concentration was at 5μM,preceding the initiation of apoptosis.Our findings demonstrate that inhibition of TRCs by anti-cancer molecule WYC-209 is concentration-dependent and WYC-209 inhibits cellular force generation of the tumor-repopulating cells before inducing apoptosis.
基金supported by grants from Chinese Academy of Medical Sciences(CAMS)Initiative for Innovative Medicine(CAMS-I2M)2017-I2M-1-001,the National Natural Science Foundation of China(81788101,81661128007,81530080,and 81773062)the CAMS Initiative for Innovative Medicine(2016-I2M-1–007).
文摘Different types of pores ubiquitously form in cell membranes,leading to various types of cell death that profoundly influence the fate of inflammation and the disease status.However,these pores have never truly been visualized to date.Atomic force microscopy(AFM),which is emerging as a powerful tool to analyze the mechanical properties of biomolecules and cells,is actually an excellent imaging platform that allows biological samples to be visualized by probing surface roughness at the level of atomic resolution.Here,membrane pore structures were clearly visualized using AFM.This visualization not only describes the aperture and depth of the pore complexes but also highlights differences among the pores formed by perforin and gasdermins in tumor cell membranes and by complement in immune cell membranes.Additionally,this type of visualization also reveals the dynamic process of pore formation,fusion,and repair.